hmm...depends on what tint you want.
I think the only black lense that is mirrored is the expensive polarized one. Dumont was rocking them in one of the Freeskier videos (empire takes over area 51) and they look pretty mirrored.
I have a pink iridium lense...and it's a dope lense...real versatile ... it is mirrored but not as dark a tint as the gold iridium etc.
The most reflective ones i think ... are the fire iridium, blue iridium etc.